Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent obstruction of the upper airway, causing apneas that are associated with oxygen desaturation and frequent arousals from sleep. The diagnosis of OSAS is usually obvious, presenting features of snoring, excessive daytime sleepiness, general fatigue, and obesity. Hochuekkito is a KAMPO medicine, Indicated for general fatigue, lack of will power, weakness of arms and legs, daytime sleepiness, gastric ptosis, hemorrhoids, prolapsus ani, ptosis of the uterus, and impotence.
Weakness of the upper airway dilator muscles induces obstruction of upper airway, and apnea. Hochuekkito may improve the muscle tone of the upper airway. The effect of Hochuekkito were studied in 13 patients with OSAS (5 patients diagnosed by polysomnography and 8 patients diagnosed by apnomonitor). The results indicate that there exist statistically significant differences in apnea index (AI) and desaturation (AI 23.1±4.8→9.6 ±2.6/h., mean SaO₂ (%) 83.7±0.7→94.0±0.9, p<0.05, mean±SD). We conclude that Hochuekkito increases the upper airway activity causing reduction of sleep apnea and snoring.

Fourty-four cases with psychosomatic disease or neurosis were studied during serial immersion in hot sulfate spring for 7 days at Sukawa Spa in Iwate prefecture. Before and after the balneotherapy, blood specimen were taken for endocrinological analysis of plasma catecholamines with use of high-speed liquid chromatography. One, two and three years after balneotherapy, long term prognostic efficacy was evaluated by questionnaire in order to examine the relationship between efficacy and changing pattern of plasma catecholamines.
The results of this study presented that the plasma levels of norepinephrine had decreased during balneotherapy in effective cases (p<0.05). Furthermore, the same changing pattern of plasma norepinephrine was observed in the cases which had improved after long interval. On the otherhand, in non-effective cases and cases with recurrence, the plasma levels of norepinephrine had increased significantly (p<0.05) during balneotherapy.
It was thought that response pattern of plasma catecholamines to serial immersion in hot spring reflected the therapeutic mechanism of balneotherapy, thus it would be an appropriate mediator for evaluating the prognosis.